That makes sense, thank you! Funny, I'm just used to looking at piers and small docks with permanant structures in place, it never occured to me one would have been made out of pontoons. Engineers missed nothing, talk about creative thinkers.
I wish someone would enlighten me on which pontoon bridge it was which was built while Confederate sharpshooters in the city on the banks kept up a game of picking off the construction engineers. forcing them to keep running out onto the bridge, bang some of it together, run off again under fire. ( I know it's book 2 of Shelby Foote's trilogy, can NOT remember what the situation was, hence which city, drat it. ) Finally a screaming bombardment of the city was ordered, houses flattened, mayhem ensued and afterwards it transpired the sharpshooters were right back at it. D*m memory. I'll know all this kind of thing after the second re-read.